The fingerprint texture for human's finger has two types of patterns: ridges and valleys. Since fingerprints vary from person to person, by verifying a person's fingerprint, his/her identity can be verified. In order to enhance the safety for operating a display apparatus, a fingerprint identification device can be arranged on the display apparatus, with which when operating some programs installed on the display apparatus requiring confidentiality, the operator is required to verify his/her fingerprint, and if the operator's fingerprint is not successfully verified, it proves that the operator has no right to run the programs.
At present, as shown in FIG. 1, a fingerprint identification device is generally composed of gate lines 02 in a row direction, data lines 03 in a column direction, a fingerprint identification electrode 01 and a thin-film transistor (TFT) 04. The gate lines 02 comprise gate lines G1, G2 . . . Gn, and the data lines 03 comprise data lines X1, X2 . . . Xn. The fingerprint identification electrode 01 has a self-capacitance function, and when a person's fingerprint touches the fingerprint identification electrode, it causes a change in the self-capacitance of the fingerprint identification electrode, such that an output signal on the data line is changed, hence the fingerprint pattern can be determined by means of an variation of the output signal. The specific operation process of the fingerprint identification device is described as follows: (a) detection signal writing-in stage: as shown in FIG. 2a, a scanning signal is applied to the gate line G1 to switch on a first row of TFTs, meanwhile, detection signals D1, D2 . . . Dn are written in through the data line 03. The area where the fingerprint identification electrode 01 is located generates a corresponding capacitance due to capacitance coupling. The capacitance would not be changed without an external influence, but when a person's finger touches the fingerprint identification device, since the fingerprint texture features the two patterns of ridges and valleys, and the distances from a ridge and from a valley to the fingerprint identification electrode are different, this would cause different influences on the capacitances generated at the fingerprint identification electrode corresponding to the positions of the ridge and the valley, resulting in different capacitance changes, (b) identification signal reading stage: as shown in FIG. 2b, identification signals D1′, D2′ . . . Dn′ that experience a change induced by the fingerprint texture are read, and sent to a processing chip through the data line 03, (c) comparison process: the processing chip compares the detection signals with the identification signals, so as to determine the ridges/valleys to which each fingerprint identification electrode unit corresponds based on an amount of variation between the detection signals and the identification signals, (d) finally, scanning signals are applied sequentially to the gate lines G2, G3 . . . Gn, and the above steps (a)-(c) are repeated until the end of scanning. It can be seen from the above process that, the data line 03 are reused for two functions, i.e., one is writing in detection signals at the writing-in stage, and the other is reading identification signals at the reading stage. Moreover, it is required to perform both the writing-in and reading for each row before executing the step of applying a scanning signal to the gate line of a next row. Thus it can be seen that the scanning will cost a longer time, the frequency of scanning is hard to increase, and the accuracy of identification is decreased accordingly.
Therefore, how to reduce the scanning time, increase the scanning frequency, and improve the identification accuracy is a technical problem to be urgently solved by those skilled in the art.